Arturo
11-13-2002, 02:19 PM
Maegele M, Muller S, Wernig A, Edgerton VR, Harkema SJ.
Department of Physiology, University of Bonn, Bonn, Germany.
We investigated the activation of lower limb motor pools by supraspinal and
spinal networks after human spinal cord injury (SCI). We compared
electromyographic (EMG) activity from six muscles during voluntarily attempted
non-weight-bearing single-joint movements, multijoint movements approximating
stepping in a supine position, and weight-bearing stepping on a treadmill with
body weight support (BWST) in seven clinically incomplete and three clinically
complete SCI subjects. Seven SCI subjects had previously completed Laufband
therapy (a specific step training using variable levels of body weight support
and manual assistance). Significant coactivation of agonists and antagonists and
multijoint flexion or extension movements of the entire limb occurred during
attempts at isolated knee or ankle single-joint movements in clinically
incomplete SCI subjects. Further, some muscles that were not recruited during
voluntary attempts at single-joint movements were activated during voluntary
step-like multijoint movements (5/16 comparisons). This suggests that the
residual voluntary motor control in incomplete SCI subjects evokes more
generalized motor patterns (limb flexion or extension) rather than selective
activation of individual muscles. Clinically incomplete and clinically complete
SCI subjects could achieve greater activation of motor pools and more reciprocal
patterns of activity between agonists and antagonists during weight bearing
stepping than during non-weight-bearing voluntary movements. The EMG mean
amplitudes were higher during stepping than during voluntary movements in 50/60
muscles studied (p < 0.05). These results suggest that stepping with knee and
hip extension and flexion and alternating lower limb loading and unloading
provides proprioceptive inputs to the spinal cord that increases motor
recruitment and improves reciprocity between agonists and antagonists compared
to voluntary efforts.
PMID: 12427330 [PubMed - in process]
Department of Physiology, University of Bonn, Bonn, Germany.
We investigated the activation of lower limb motor pools by supraspinal and
spinal networks after human spinal cord injury (SCI). We compared
electromyographic (EMG) activity from six muscles during voluntarily attempted
non-weight-bearing single-joint movements, multijoint movements approximating
stepping in a supine position, and weight-bearing stepping on a treadmill with
body weight support (BWST) in seven clinically incomplete and three clinically
complete SCI subjects. Seven SCI subjects had previously completed Laufband
therapy (a specific step training using variable levels of body weight support
and manual assistance). Significant coactivation of agonists and antagonists and
multijoint flexion or extension movements of the entire limb occurred during
attempts at isolated knee or ankle single-joint movements in clinically
incomplete SCI subjects. Further, some muscles that were not recruited during
voluntary attempts at single-joint movements were activated during voluntary
step-like multijoint movements (5/16 comparisons). This suggests that the
residual voluntary motor control in incomplete SCI subjects evokes more
generalized motor patterns (limb flexion or extension) rather than selective
activation of individual muscles. Clinically incomplete and clinically complete
SCI subjects could achieve greater activation of motor pools and more reciprocal
patterns of activity between agonists and antagonists during weight bearing
stepping than during non-weight-bearing voluntary movements. The EMG mean
amplitudes were higher during stepping than during voluntary movements in 50/60
muscles studied (p < 0.05). These results suggest that stepping with knee and
hip extension and flexion and alternating lower limb loading and unloading
provides proprioceptive inputs to the spinal cord that increases motor
recruitment and improves reciprocity between agonists and antagonists compared
to voluntary efforts.
PMID: 12427330 [PubMed - in process]